I'm a little confused on your subject. If it is the sky and clouds, it may be a good idea to show some contrast between the two. Also, some good saturation my be necessary when you post process. A CPOL might have made a difference here because of the low angle of the light.

Cool photo of a bird's nest but the big blurry leaf on the left said is somewhat distracting. Maybe you can crop some of the left side of the photo or retake using "rule of thirds" to remove the near leaf. Also, some vignetting can place the viewer's attention more toward the nest.

Good focusing here. I wouldn't make any major changes. At most, I would just little tweak on saturation and contrast. And a little vignetting wouldn't hurt.

Hey PL... I could comment a bit on the technical aspects (such as the lack of focus on 1 and 4... try manual focus next time on these), but really the key thing is there isn't much of a subject in these.

I mean that birdnest is actually kind of fascinating, but the picture is unfortunately not that interesting (and I didn't know it was a bird nest!) Totally bizarre. Some bird had fun.

The dogs are somewhat of a subject, but it mostly just looks like a pic of a couple of dogs behind a not-so-pretty fence. Nothing too interesting.

For me, this is the toughest part of photography... not just getting a technically good shot, but one with interest as well. The "rule of thirds" helps (look it up if you're not familiar with it), and sometimes funky angles or lighting can be your friend... but in the end, I think a lot of it is trying to figure out if the photo is going to really grab you in some way... or perhaps say something... or perhaps have remarkable colors, patterns or textures.

Not easy to do.

Keep trying and keep posting. Lots of people here will give you some great tips.

C&C per req:
To be honest, there's not a lot to critique on; images 1 and 4 are a slightly orange sky with unfocused tree-tops,

2. appears to be a close-up of some sort of unusual plant; for this type of work, try and shoot down onto the flower rather than side on. Also note that you have a lot of branches in the foreground which are between the eye and the subject.

3. Would be a cute picture but for the fence. There are some photographs that really aren't worth taking. If you could have positioned yourself on the other side of the fence, it would have worked well, alternatively, you could have watited until the dogs were farther back, got as close to the fence as you could and shot dogs wide open. This would have minimized the appearance of the fence.